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S Konturek

Publications and source records attributed to S Konturek.

At least 19 recordsLinked to original sources
PubMed1988

Angiogenesis: quantitative assessment by the chick chorioallantoic membrane assay.

The aim of the present work was to improve quantitative assessment of angiogenesis by chick chorioallantoic membrane (CAM) assay based on measurement of DNA synthesis. Following incubation of [3H]thymidine (3H-T) with CAM in vivo, incorporation of 3H-T to DNA fraction was expressed as percent of total 3H-T present in the initial homogenate of CAM, regardless of CAM weight and full recovery of applied radioactivity. The assay required simple, partial isolation of DNA to remove traces of free or unspecifically bound 3H-T. These modifications gave a reproducible assay with adequate precision (10-20%). DNA content of CAM did not change between 10-15 days of embryo development and growth of CAM was completed on day 11. 10 to 12-day old CAMs were used for evaluation of the assay. Using a qualitative approach (visual scoring), tissues of several tumors were implanted on CAM. Extracts of tumors that produced the highest score stimulated DNA synthesis in CAM. A similar effect was induced by EGF while cytostatics inhibited DNA synthesis in CAM. Since stimulation of angiogenesis is not a cell type-specific phenomenon, the assay in the present modification should aid the studies on angiogenic factors. With the help of this assay the angiogenic activity of adenocarcinoma of human endometrium was described.

Allantois↗
PubMed1987

Effect of partial versus complete pancreatic denervation on pancreatic secretion.

The aim of this study is to compare the effect of various stimuli on pancreatic secretion in two groups of dogs, one undergoing interruption of the cholinergic and adrenergic branches to the pancreas (long arc reflexes), and the second group undergoing total denervation of the pancreas by its isolation from stomach and duodenum (short arc reflexes). Stimulation of pancreatic secretion was accomplished by (a) hormonal, by i.v. secretin and CCK/PZ and (b) reflex stimulation by intraduodenal administration of fat (Na oleate) or amino acids (Aminosyn). After a few weeks of collected data in stimulated controls, the dogs were divided into two groups: (A) Four dogs underwent proximal truncal vagotomy, celiac ganglionectomy, and stripping of the common hepatic and gastroduodenal arteries for 2-3 cm. (B) Four dogs underwent the same procedures, but in addition the pancreas was dissected away from its vascular and nervous attachments to the duodenal wall and pyloric region, as well as from its mesenteric and peritoneal attachments. All animals were then tested with secretin, Cholecystokinin/pancreozymin (CCK/PZ), intraduodenal fat, and intraduodenal amino acids. The data obtained indicate that secretion of pancreatic bicarbonate is dependent on intact local duodeno-pancreatic nervous reflexes. Fat and amino acids stimulate the secretion of bicarbonate only when the attachments of the pancreas to the stomach and duodenum are intact. Stimulation by secretion or CCK, being humoral-hormonal mediators, appears not to be affected by the local denervation.

Amino Acids↗
PubMed1980

[Physiology and pathophysiology of bile secretion].

After introductory anatomical considerations a survey is given of the composition of bile and the physiology of bile secretion. According to the modern conception the bile acids give the osmotic power for the excretion of water and electrolytes. Apart from this, a bile fraction, which is also secreted by the liver cells into the canaliculi, is present, and in the biliary ducts a further volume fraction independent of bile acid is added, the secretion of which is determined by gastrointestinal hormones. Processes of reabsorption play a role particularly in the gallbladder. By formation of micelles the bile salts render the excretion of cholesterol possible. A normal bile secretion is necessary for the normal emulgation, digestion and absorption of the fats.

Bile↗